1. Field of the Invention
The present invention relates to an apparatus for dressing shoulders on tubular threaded connections. More particularly, the present invention relates to a portable shoulder dressing apparatus operable for dressing two shoulders simultaneously.
2. Description of the Background
Tubular goods used as drill pipe for drilling a well typically include tubular connectors for threadably interconnecting the drill pipes together. Certain types of tubular connectors include two shoulders on each connector. One of these shoulders, the seal shoulder, provides a seal that may be a relatively high pressure seal and also acts to preload the threaded connection. The other shoulder acts as mechanical stop to minimize damage from over-torquing of the connection.
The two shoulders on each connector must be smooth, flat and parallel to each other. The axial distance between the two shoulders, referred to as pin length or box depth, is important for proper operation of the connection. A typical tolerance on the axial distance may be in the range of +0.000 inches and -0.005 inches. The primary shoulder or seal shoulder is the radially outermost shoulder on the connector. The secondary shoulder or stop shoulder is radially inwardly disposed with respect to the seal shoulder.
The shoulders may require redressing for a number of reasons including the following reasons: (a) They can become damaged and will not seal the drilling fluid that is pumped, under pressure, through the drill pipe; (b) they become damaged in such a way that a mating, or corresponding shoulder becomes damaged; (c) the pin length or box depth has changed because of over-torquing during makeup of the drill string and subsequent yielding of the pin nose or box counterbore; and when the seal shoulder of a pin or box is redressed, the stop shoulder on that member may also need to be redressed to maintain the correct pin length or box depth.
In the past, when redressing was required, it was necessary for the operator to send the drill pipe to a machine shop for repair work. Transportation costs, machining costs, and loss of length from recutting were disadvantages associated with redressing the shoulders. Specifically designed shoulder dressing tools were expensive and bulky so as to effectively prohibit field use of such dressing tools.
Consequently, there remains the need for an improved shoulder dressing tool that is portable, dependable, provides the accuracy necessary in shoulder dressing, and that may be obtained and operated at reduced levels of capital investment. Those skilled in the art have long sought and will appreciate the present invention, which provides solutions for these and other problems.